fs tree invalid on APFS

hello,

while doing a first-aid check on my macOS APFS volume, I get the following message in the details as it scans the volume. it is

Checking the fsroot tree.

error: drec_val object (oid 0x51b169): invalid type (0)

fsroot tree is invalid.

The volume /dev/rdisk1s1 could not be verified completely.

can anyone who's knowledgeable with this type of error provide some info about what this error is, whether it's a concern or not ?